SOMEONE HELP ME PLEASE!!!!!

Two of the three tuning forks have known frequencies. When a 510 Hz. fork and the unknown fork are struck together, four beats p

Vikki [24]

4 Hz is the difference between 510 and the unknown.
Therefore the unknown is either 514 or 506. 

If 505 and 506 were struck together, the diff would be 1 Hz 
If 505 and 514 were struck toghether, the diff would be 9 Hz which would be difficult to count accurately, 

Therefore the unknown is 514

3 0

4 years ago

Two lightbulbs work on a 120-V circuit One 50 W and the other is 100 W. Which bulb has a higher resistance? Explain pls!!!!

Sladkaya [172]

Answer:

Bulb 1 has more resistance.

Explanation:

Given that,

Two lightbulbs work on a 120-V circuit.

The power of circuit 1, P₁ = 50 W

The power of circuit 2, P₂ = 100 W

We need to find the bulb that has a higher resistance.

The power of the bulb is given by :

$P = \dfrac{V^2}{R}$

For bulb 1,

$R_1=\dfrac{V^2}{P_1}\\\\R_1=\dfrac{(120)^2}{50}\\\\R_1=288\ \Omega$

For bulb 2,

$R_2=\dfrac{V^2}{P_2}\\\\R_2=\dfrac{(120)^2}{100}\\\\R_2=144\ \Omega$

So, bulb 1 has higher resistance.

8 0

3 years ago

An a.c. supply is connected to a wire stretched between the poles of a magnet. Which way does the wire move?

snow_lady [41]

The wire vibrates back and forth between the poles of the magnet.
The frequency of the vibration is the frequency of the AC supply.

7 0

2 years ago

A human being can be electrocuted if a current as small as 55 mA passes near the heart. An electrician working with sweaty hands

evablogger [386]

Answer:

The lethal voltage for the electrician under those conditions is 126.5 V.

Explanation:

To discover what is the lethal voltage to the electrician we need to find out what is the voltage that produces 55 mA = 0.055 A when across a resistance of 2300 Ohms (Electrician's body resistancy). For that we'll use Ohm's Law wich is expressed by the following equation:

V = i*R

Where V is the voltage we want to find out, i is the current wich is lethal to the electrician and R is his body resistance. By applying the given values we have:

V = 0.055*2300 = 126.5 V.

The lethal voltage for the electrician under those conditions is 126.5 V.

4 0

3 years ago

Read 2 more answers

You are sitting on a merry-go-round of mass 200 kg and radius 2m that is at rest (not spinning). Your mass is 50 kg. Your friend

Bogdan [553]

Answer:

a. $\tau=200J$ b. $\alpha=0.44 \frac{rad}{s^2}$ c. $\alpha=0.33\frac{rad}{s^2}$ d. The angular acceleration when sitting in the middle is larger.

Explanation:

a. The magnitude of the torque is given by $\tau=rF\sin \theta$ , being r the radius, F the force aplied and $\theta$ the angle between the vector force and the vector radius. Since $\theta=90^{\circ}, \, \sin\theta=1$ and so $\tau=rF=2m100N=200Nm=200J$ .

b. Since the relation $\tau=I\alpha$ hols, being I the moment of inertia, the angular acceleration can be calculated by $\alpha=\frac{\tau}{I}$ . Since we have already calculated the torque, all left is calculate the moment of inertia. The moment of inertia of a solid disk rotating about an axis that passes through its center is $I=\frac{1}{2}Mr^2$ , being M the mass of the disk. If we assume that a person has a punctual mass, the moment of inertia of a person would be given by $I_p=m_pr_p^{2}$ , being $m_p$ the mass of the person and $r_p^{2}$ the distance from the person to the center. Given all of this, we have

$\alpha=\frac{\tau}{I}=\frac{\tau}{I_{disk}+I_{person}}=\frac{Fr}{\frac{1}{2}Mr^2+m_pr_p^{2}}=\frac{200Nm}{\frac{1}{2}200kg*4m^2+50kg*1m^2}=\frac{200\frac{kgm^2}{s^2}}{450Nm^2}\approx 0.44\frac{rad}{s^2}$ .

c. Similar equation to b, but changing $r_p=2m$ , so

$alpha=\dfrac{200\frac{kgm^2}{s^2}}{\frac{1}{2}200*4kg\,m^2+50*4 kg\,m^2}=\dfrac{200}{600}\dfrac{1}{s^2}\approx 0.33 \frac{rad}{s^2}$ .

d. The angular acceleration when sitting in the middle is larger because the moment of inertia of the person is smaller, meaning that the person has less inertia to rotate.

5 0

3 years ago